1. Field of the Invention
The present invention is directed to an apparatus for and method of separating suspended particulate matter from an effluent, and comprises a cylindrical separator tank having a substantially flat bottom including an elongate trough having an upper portion which is in free, open communication with the interior of the tank. When the particle-laden effluent is introduced into the tank, the floatable particulate matter suspended therein floats to the surface of the effluent and may be effectively skimmed therefrom, whereas the sedimentary or settleable particulate matter suspended therein settles as sludge at the bottom of the tank. The sludge at the bottom of the tank is scraped into the elongate trough and is transported to an outlet outside the tank wherein a substantially vertical conveyor-elevator elevates the sludge from the outlet to a discharge port above the fluid level of the tank.
2. Description of the Prior Art
Heretofore, it has been the custom to remove settleable particles from an effluent by passing the effluent through the separator tank of a conventional clarification system, wherein the settleable particles settle to the bottom of the tank and are collected at a central sump or pit in communication therewith. A scraper or the like at the bottom of the tank is utilized to transfer the settled particles into the sump, after which the particles are pumped from the sump in the form of sludge. In general, the sludge is excessively high in fluid content, and in some instances comprises as much as 98 percent water.
This problem has long plagued the meat packing industry, wherein the effluent which transports waste material from slaughtering and dressing operations generally includes grease, animal hair and nails, blood and other organic material which cannot be discharged into conventional sewage disposal systems. The effluent is first passed through a screening or filtering process wherein the larger solid particles are removed, resulting in a "dirty" effluent which includes floatable and settleable particles which are too small to be screened or filtered therefrom. The "dirty" effluent is introduced into the separator tank of a conventional clarification system, wherein the floatable particles such as grease, scum and the like accumulate at the surface of the effluent, and wherein the settleable particles settle out of the effluent at the bottom of the tank. The floatable particles are effectively skimmed from the surface of the effluent and collected for further processing, whereas the settled particles are collected at the central sump and discharged as sludge for subsequent disposal. The remaining, "clean" effluent is free of both settleable and floatable particles and may be discharged from the separator tank into conventional sewage disposal systems.
The sludge which is discharged from the tank is exceptionally high in fluid content, and before the solid waste therein may be suitably disposed, the sludge must be subjected to lengthy cooking and drying operations, wherein the fluids are removed through evaporation.
In the past, systems have been devised which provide an inclined conveyor in communication with the bottom of a tank, wherein sedimentary particulate matter is elevated to and discharged at a point above the fluid level of the tank, as shown, by way of example, in U.S. Pat. Nos. 2,189,418; 2,635,104 and 2,843,270. Further, it is known to provide an inclined conveyer in communication with the bottom of a conical separator tank, such as disclosed in U.S. Pat. No. 1,648,607 wherein centrifugal forces and gravity are utilized to separate suspended particulate matter from a fluid.